Last year I took on a challenge: growing sweet potatoes in the Pacific Northwest, known for being cool and rainy. I’m actually located right near Portland, OR, but across the river in wetter Washington State.
People hinted to me that it wouldn’t work.
Might as well find out, right? I started with organic sweet potatoes from Costco. Nothing special. Thinking back on it now, I probably should have picked a short-season variety for better success. Territorial Seed has a few varieties that work better in cooler, shorter climates.
Starting Sweet Potato Slips
Somewhere I had read that you should start your sweet potato slips around April 18th. However, if I were to do it again, I would probably start growing my slips much earlier – maybe even January.
I began by cutting three sweet potatoes in half, and placing them cut side down into bread pans. I then filled the pans with water 1/2 inch deep, and set them in the warmest place in the house – the kitchen window. Then I began to wait. And wait. And wait. See the video below for details on starting your own slips.
It took a very long time, about 4 weeks to be precise, but finally the potatoes began to sprout. Once they started, they took off! When a slip was about 8 inches tall, I would break it off and place it in a glass of water where it would grow roots. Meanwhile, the sweet potato would grow more slips!
About a week after placing the slips in the glass of water, they would have some well established roots. At this point, I planted each slip into a 4″ pot of soil. This step really depends on the weather – if it is June and already quite warm, you can actually plant the rooted slips straight into the garden.
I planted my potted sweet potatoes (and some new slips with roots) into the garden on June 7th. I made sure my garden bed was in full sun, and tried to slant the bed slightly south for more direct sun-exposure. I didn’t quite have enough slips to fill my 4′ x 8′ garden bed, so I continued to grow more slips and plant them as they were ready.
When to Harvest Sweet Potatoes
The sweet potatoes grew all summer long, with minimal maintenance required. I did weed a few times, and watered regularly. I had read online that sweet potatoes may be left in the ground until the first frost, but I couldn’t quite wait that long. I harvested mine on October 26th. I was happy to find quite a few medium-large sweet potatoes, and quite a few smaller ones! However, some sort of critter (maybe rats) had harvested more than half of my plants before I did. This was disappointing, but overall it was a successful year growing sweet potatoes! Now I know that it IS possible to grow sweet potatoes in the Pacific Northwest.
Watch the video below to see our harvest and other tips on growing your own sweet potatoes.
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I am surprised to see that maybe I can grow sweet potatoes because I love them in just about everything. I live in Aberdeen on the Wash. coast. I think I will give this a try. Where did you find your seed potatoes?
Linda, we just used organic sweet potatoes from Costco! Good luck!
Hi I grew some last year in tulalip WA last year. Planted them in middle of may in an old cattle trough filled with rotting fence post at the bottom horse manure covered grass clippings and potting soil. Then coveted the seedlings with plastic lettuce boxes as mini greenhouse. Left on vacation for a week. Came back they had survived looked a tiny bigger. By august plants were finally veining onto the ground below. While I didn’t get a bumper crop about 16 good sized fruit for 8 plants. But many pencil thin carrot like roots. Will save those for this spring.to try as experiment. Want to try in ground this year.
So…… Linda…… How did they do? We live in Montesano, and would like to try growing them. Mark
Hello Matthew
I was all set to try this last year when the supplies for my slips did not come through…Southern Seed Supply…though I contacted them three times about the issue and they kept telling that we were on a later ship date for Washington. I already know that I have an issue in my beds with R_A_T_S, but also have the crows (wait on the fence to pull up new brassica starts), possums and raccoons to contend with. I think that the black mulch that I already put in place would not only help with the critters but would make your beds warmer perhaps. I really appreciated your article and will absorb all your helpful advice. Merci’. Have you tried watermelon yet?
Susan, I did try watermelon a couple times. Had good success with “Moon and Stars” variety one year. The hardest part is knowing when they are ripe, and also keeping the slugs away from them. Good to hear from you!
This is very helpful. I look forward to trying to grow sweet potatoes in Marysville WA. Thank you
I gru tham in southwest washington they looked more like carrots than potatoes
I started Kumara slips four weeks ago. Slow start but have them beside the wood stove and they going great, got hundreds. I’ve begun harvesting, putting them in water. My aim is to have them ready for planting out by mid April. (Central France).
We can have light frosts until May, so cover them.
How did you ever get your hands on Kumara? I love it! But cannot find it in Canada!
Mail me some?
What type of soil did you use?
I live also in the pacific northwest and I would like to grow sweet potato in a container I tried last year but I throught you plant the whole potato in the container also what is the best brand to buy I have other potato that I got a very large number of them the ones I cut in half did not do well the sweet potato I put the whole thing in I lived in a senior apartment and I have a very large balony I also grew collards, celery , green beans they all did very well. did you break off the vine your video did nor show that and what do you do with the sweet potato afterwards are they still eatable? HELP
I receive sweet potatoes slips from burpee Friday 4/12/19 I have them in water because it is raining and the sun will be out until Wednesday I am planting them in a container this is the second time I have wrote to you have not receive answer from the first one should I plant them now? or can the keep in water until Wednesday
Hi Mary! Do the slips have roots on them? If not, I’d keep them in water until they grow some nice roots. If they have roots, I would plant them in pots. I probably wouldn’t plant them outside until mid May at least, just to be safe from frost.
I live in seattle I am a senior I have a balony last year I grew collards something ate them
I would like to grow sweet potates I grew red and yellow they did wonderful what brand
sweet potatoes are best for pacific northwest? where do you put them after they are ready?
why do you leave them a few days after harvesting them. thank you
Is there a certain brand name I should buy? besides being organic I will be growing them in container I saw some organic sweet potato at trader joes but they were small also saw some sweet potato at gurneys 21.00 and burpee same price should I or should I buy them? I am a senior living in a senior apt. and have a very large wrap around balony/ help
Hi Mary! When I tried this, I just used organic sweet potatoes that I bought at the store. Otherwise, you might want to special order some from Territorial Seed – they have some that work better with the short growing season. Hopet his helps!
I plante sweet potatoes in container today on my balcony it is warm nights 40 will my slips die I kept them a whole week before I planted them I ordered for burpee I was afraid to keep them in the house later they hsd roots when I receive them
Hi Mary! I’m not sure. Maybe ask Burbee – it might depend on the type of sweet potato.